Treatment of casein or the like protein fibers



Aug. 21, 1945.

R. WORMYELL Q 2,383,358

TREATMENT OF CASEIN OR THE LIKE PROTEIN FIBERS Filed Nov. 18, 1945 FIG.3. 7,

INVENTOR ROBERT LOUIS. WORMELL BY W ' H ATTORNEYS Patented Aug. 21, 1945 TREATMENT OF CASEIN on THE LIKE PROTEIN FIBERS Robert Louis Wormell, Coventry, England, assignor to Courtaulds Limited, London, England, a

British company Application November 18, 1943, Serial No. 510,817

In Great Britain January 25, 1943 1 Claim. (Cl. 8-1512) This invention relates to the hardening or other treatment of a continuous tow of casein or the like protein fiber. Under the term "casein or the like protein" I include animal casein derived from milk and vegetable casein or globulins such as those derived from soya beans, pea-nuts and the like. Under the word "tow I include a bundle or thread of continuous filaments and also a bundle or thread of staplefibers, provided these latter are sufllciently adherent.

In the preparation of artificial textile fibers from casein, the casein is dissolved in alkali and fibers are obtained by extruding the solution through spinning nozzles into a coagulating bath containing acid and salts. Fibers from several spinning nozzles are frequently combined to form a tow and the tow is subjected to one or more hardening or other treatments. As the hardening or other treatment is carried out for a considerable time care must be taken to avoid tangling of the fibers in the hardening bath.

I have now found that I can continuously treat a tow of casein or the like protein fibers by continuously feeding the tow in convolutions on to the surface of a hardening liquid of specific gravity greater than the specific gravity of the'fibers so that the convolutions of the tow float on or in the treating liquid, allowing the tow to accumulate in the liquid for sufiicient time to produce the desired effect and thereafter continuously withdrawing the tow from the treating liquid at a rate substantially equal to the rate of feed liquid, the tow, according to one embodiment of the invention is conducted through a tube, the entrance arm of which is situated below the mass of convolutions. The exit arm of the tube may be situated inside or outside the bath of liquid. In the former case the exit arm is positioned away from the mass of convolutions, as for example close to the side wall of the bath, and may terminate above, below or at the level of the liquid in the bath. When the exit arm is situated outside the bath, the tube may pass through the side wall of the bath at a convenient distance below the mass of convolutions of the tow. The exit arm may terminate at a higher level than the surface of the treating liquid, or if desired,

the exit arm may terminate at or slightly below" tube in order to facilitate the passage of the tow. Instead of conducting the tow through a tube, it may be conducted through a device such as a pulley, or a hook or hooks, or bars positioned below the mass of convolutions of the tow and thence out of the liquid bath in a direction away from the mass of convolutions.

The treating liquid is contained in a tank of suitable dimensions which may for instance be in the form of a cylindrical container in which case it is preferred to maintain a slow circulatory motion of the liquid in the tank. The tank may alternatively be of long rectangular form in which case a slow current of treating liquid may be maintained to float the tow along to the tube. The surface of the liquid in the tank may be maintained at a pressure less than atmospheric pressure in order to remove any objectionable vapours. If desired the tow may be continuously fed on to the surface of the treating liquid by means of traverse feeding mechanism.

In the process according to the present invention the tow may remain in the bath for any convenient time, for example, from 1 to 2 hours and is then removed from the underside of the mass of convolutions thus avoiding the risk of tangling of the tow. The process may be used for the purpose of giving a preliminary hardening to the tow, for example with an aqueous solution containing 420 grams of sodium sulphate and 10 grams of formaldehyde per litre of solution. The process may also be used to complete the treatment of partially hardened tow, so that it becomes resistant to boiling water and boiling dilute acids, a suitable bath for this purpose being an aqueous solution containing 496 grams of sulphuric acid, 2'71 grams of sodium sulphate and 28.5 grams of formaldehyde per litre of solution. Examples of other baths suitable for this latter purpose are described in U. S. Serial No. 440,116.

The present invention is illustrated by way of example in the accompanying diagrammatic drawing in which Figures 1 and 2 show suitable apparatus for feeding the tow in convolutions on to the surface of the hardening liquid, Figure 2 being a section along the line AA of Figure 1; Figure 3 illustrates an embodiment of the invention employing a guiding tube, and Figure 4 illustrates an embodiment employing two books asthe guiding means.

The feeding device shown in Figures 1 and 2 comprises a shaft l fitted to driving means not shown, and on to the shaft are fixed end supports 2 and 3. A tube 4, which is suitably made of glass, is loosely fitted over the shaft between the supports 2 and 3 and a rod I is also fixed into the supports 2 and 8.

In operatiori' the shaft I is rotated by any suitable driving means and the initially extruded end of the tow I is led over the tube 4 and the rod 5 and thence to the liquid bath I (Figures 3 and 4) the tow falling in convolutions 8 on to the surface of the liquid. As the specific gravity of the liquid is higher than the specific gravity of the fibersof the tow, the latter floats in the liquid as shown. After the tow has been allowed to accumulate in the bath for the required time, it is removed continuously from the bath either through the tube 9 as shown in Figure 3, or through the hooks i0 and II as shown in Figure 4.

In an alternative form of feeding device the tube 4 may be replaced by two rods, similar to the rod 5, fixed into the supports 2 and 3 and arranged a short distance from and on opposite sides of the shaft I.

If desired, a slow circulatory motion of the liquid 6 may be maintained by continuously withdrawing liquid, as by a pump, at a point near the bottom of the tank and feeding it back to the tank through one or more pipes positioned near the surface of the bath of liquid. In order to ensure uniform hardening of the tow in the liquid, the tow may be given a short preliminary impregnation with the hardening liquid just before being fed in convolutions on to the surface of the hardening bath.

Although it is preferred to employ some form of device such as that illustrated for feeding the tow in convolutions on to the surface of hardening liquid, such a device is not essential for the purposes of the present invention; the desired effect may for example be obtained by allowing the tow to fall directly on to the surface of the liquid in which a slow circulatory motion is maintained.

What I claim is:

A process of treating a tow of casein or the like protein fibers with a hardening liquid of specific gravity greater than the specific gravity of the fibers which consists in continuously feeding the tow in convolutions on to the surface of a bath of the said liquid so that the convolutions of thetow float on or in the liquid, allowing the tow to become at least partially hardened in the liquid and thereafter continuously withdrawing the tow from the treating liquid at a rate substantially equal to the rate of feed by removing the tow from the underside of the mass of convolutions and then conducting the tow out of the liquid through guiding means situated below the level of the underside of the mass of convolutions so that entanglement of the tow is avoided.

ROBERT LOUIS WORMELL. 

